@mattdm I'm not sure how to describe the blur in general terms that others might use in the future -- 'radial' blur? Would someone else use that term? I don't know. If you look at the image feel try to add a description. I was guessing it was a Petzval lens because images taken with that lens seem to have the same same background radial blue with the subject in focus.
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user151841Jan 28 '14 at 14:12

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It could very well have been taken with a vintage petzval lens, however there are many other lenses also capable of creating a similar swirling Bokeh effect as you see in this image. Ultimarely it is unlikely that you would be able to tell for sure which lens was used without asking the photographer.

Here is a list of a few other lenses that are famous for creating the "swirl"

Helios 44-2 58mm F2

Helios 44-6 58mm F2

Helios 44-7 58mm F2

Carl Zeiss 1Q Biotar 58mm f2 (10 blades version)

Carl Zeiss 1Q Biotar 58mm f2 (17 blades version)

Helios Cyclops 85mm F1.5

Recently a kickstarter campaign raised the funds to recreate Petzval lenses with modern mounts: http://microsites.lomography.com/petzval-lens/ Though they are not shipping to the public until June 2014 so I imagine that it is unlikely that the shot you linked was taken with one.

I think that the early founders of the project have received their Petzval already. At least I spotted one here (look down at the seventh photo) and I have seen a review... here
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RmanoJan 28 '14 at 23:17

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Ya, I'm sure several people have shot with it already, however, I merely was commenting that the odds of the image the OP posted being one made by one of those people is probably fairly low.
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rcooper102Jan 29 '14 at 23:34